Method of operating internal-combustion engines.



J. w. PlTTsQ METHOD OF OPERATING INTERNAL COMBUSTION ENGINES. APPLICATION FILED FEB. 14. 1912. I I 1,136,715. Patented Apr. 20, 1915.

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Al/omey L'W. PlTTS.

METHOD OF OPERATING INTERNAL COMBUSTION ENGINES. APPLICATIYQN FILED FEB. 14, 1912.

1, 136 ,7 1 5. I Patented Apr. 20, 1915.

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JOHN W. PIT'IS, OF BISIBEE, ARIZONA. I

\ METHOD OF OPERATING IN TEItNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

Patented Apr. 20, 1915.

Application fil ed February 14, 1912. Serial No. 677,627.

To all whom it may concern Be it known that I, JOHN W. Prr'rs, a citizenof the United States, residing at Bisbee, in the county of Cochise, State of Arizona, have invented certain new and useful Improvements in Methods of Operating Internal-Combustion Engines, of which the followingfi's a description, reference being had to the accompanying drawings, formin a part hereof.

. y invention relates-to methods of operating'internal combustion engines and has for its object to provide for operating such engines at the maximum efiiciency per unit of fuelconsumed when it is desired to run the engine at less than its maximum power.

Ordinarily when an internal combustion engine is run at less than its full maximum as regards development of power more fuel is consumed per 'unit of power developed than when run at its full maximum as the character of the charge, that is the relative proportion of air to fuel, cannot be materially varied in the direction of increasing the-proportion of ,air or the mixture will cease to be explosive and the amount of the charge taken into the cylinder cannot be materially reduced as, if reduced, it may not be brought in contact with the igniter at the proper time or will not be compressed to the degree necessary in order that to be so burned as to secure from the fuel its full unit efliciency.

It follows necessarily and is the case in the practical operation of internal combustion engines that the amount of fuel consumed when running with reduced load is not materially less than when running with full load with the result that fuel is wasted and the efficiency per unit of fuel consumed is less than when running with full load.

By the method of my present invention I am able to materially reduce the volume of explosive mixture taken into the cylinder at each charge without reducing the volume of the charge, thus insuring the complete filling of the cylinder at each charge so that the degree of compression will be always the same and the partial charge of explosive mixture will be exploded under the same compression at which it would be exploded if the charge were a full charge of explosive mixture. .In order to carry out my method with this result I make up a charge, either in the compression chamber or in the cylinder consisting in part of explosive mixthan the crank chamber.

ture in such proportion as may be desirable and in part of inert gas or gases containing no substantial proportion of either hydrocarbon or oxygen I. prefer touse, as such inert gas the burned gases from previous explosions and to take these gases from the exhaust. By doing so and introducing these spent or burned gases with the partial charge of explosive mixture so that the mixture will be drawn or forced into the cylinder, the total volume will be only the vol ume necessary to fill the cylinder and the greater the volume of spent gases drawn or forced in the less will be the volume of explosive mixture and, of course, the less amount of gasolene or other fuel which can be taken into the cylinder. By regulating the relative amount of spent gases thus drawn or forced in the relative amount of explosive mixture will be regulated even though no change be made in the size of the opening through which the gasolene or other fuel is admitted to the carbureter.

With these and other objects in View my invention consists in the method hereinafter described and claimed.

It will of course be understood that the drawings presented herewith are illustrative of my method.

Inv the drawings Figure 1 is a vertical sectional view of a two cycle internal combustlon engine provided w1th means for carrying my invention into efl ect and having a compression chamber for the charge other lar view of a two cycle engine in which the charge is compressed in the crank chamber, and Fig. 3 is a similar view of a four cycle engine.

In the drawing 1 is the cylinder of the engine which may be of any type, two cycle as shown in Figs. 1 and 2 or four cycle as shown in Fig. 3 or six cycle if desired. The cylinder may be provided with a water jacket 2 or may be otherwise cooled or not cooled. j

3 indicates the piston connected in any convenient manner with the engine shaft 4 being shown in Fig. 1 carried by a piston Fig. 2 1s a simiing in ways 8 and connected by pitman 9.

with crank 10 on the engine shaft 4.

In the engineshown in Figs. and 3 the pitman 9 is connected directly with the piston 3. 11 is the inlet port of the engine cylinder being shown in Fig. 1 as a series of ports leading from the compression chamber 12 which in this construction surrounds the lower end of the cylinder, and being shown in Fig. 2 as a single port leading from the crank case 13, while in Fig. 3, this inlet port is in the upper end of the cyl nder and leads from the pipe 14 leading from the carbureter.

by the piston 3 while in the engine shown in Fig. 3 the inlet port isopened and closed by a valve 13. In the upper end of the cylinder is an exhaustport 1 controlled by an inwardly opening valve 17 arranged to be opened and closed by any convenient means operated from the engine shaft as by a cam 18 on a counter shaft 19 driven by gearing from the engine shaft and operating against the endof a. rod 20 which at its upper end .is connected to a lever 21 pivoted at 22 and connected at its other end to valve rod 23 on which valve 17 is carried. 24 is a-gcarbureter of any desired construction arranged to deliver explosive mixture into pipe 14"which leads to the compression chamber 12 in Fig. 1, to the crank chamber 13 in Fig. 2 or'directly to the cylinder as in Fi 3: In Figs. 1 and 2 the pipe 14 is provi ed with a check valve 25.

The charge after compression in the engine cylinder may be ignited in any way. A spark igniter 26 is here'shown and when an igniter of this kind is used it is preferably located in the side of the cylinder at a point only slightly above the end of thepiston when it-is at the limit of its compression stroke. 27 is a pipe leading from the .exhaust port in the usual manner which may or may not be provided with a muflier (not shown). From any convenient,point in this exhaust pipe 27 a pipe 28 leads to a point in the pipe 14. This pipe 28 is controlled by a valve 29.

' The engines shown operate in the usual manner of engines of the type to which they belong, the engines of Figs. 1 and 2 drawing thecharge into the compression chamber 12 or crank case 13 as the case may be upon the compression stroke of the piston, compressing it in the compression chamber or crank case on the outward stroke of the piston opening the inlet ports at the end of the stroke to permit the charge to rush into the cylinder, compressing the charge in the cylinder on the compression stroke and igniting it when compressed all as is usual in two cycle engines. The engine of Fig. 3 operates in the manner usual tov four cycle en- When the engine, whatever its type or construction, is to be run with less than full load or to give less than its maximum power, the valve 29 is opened more or less, admitting spent gases from the exhaust pipe 27 through pipe 28 to the pipe 14 and through it into the compression chamber 12, in Fig. 1, the crank chamber 13in Fig. 2 or the engine cylinder in Fig. 3, where they mix more or less with *the explosive mixture coming from the carbureter,it being understood that by reason of the length of pipe 27 or by use of a vmufiler or otherwise there In the engines shown in Figs, 1 and 2; theinlet port or ports "are opened and closed acid thus drawn in necessarily takes up more or less of the available space leaving a p01.-

I tion only of the space to be occupied by the explosive mixture thus'serving to prevent the entrance of more than a portion of a full charge of explosive mixture even when the discharge opening of the carbureter is wide open. By opening or closing the valve .29 more or less not only will the admission of spent gases beecontrolled but this will also re ulate the admission oi explosive mixture.

he volume of-the charge whatever the.

proportions of spent gases and explosive mixture will always be the same and will be thesame as that of a full charge of explosive mixture. Consequently the compression will bealways the same or substantially the same and the partial charge of explosive mixture will be exploded and will be burned under the same conditions as those under which a full charge is exploded and burned. The

spent gases being inert not carrying any apprecla le amount of either oxygen or hydro carbon merely fill up space in the cylinder with the same efi'ect as if the cylinder were I temporarily much smaller. I

The pipe 28 is shown as coiled for the purpose of lengthening the distance through which the spent gases have to travelin passing from'theexhaust pipe to the pipe 14 and thus permitting them to cool somewhat. These coils may, if desired, be dispensed with and the pipe 28 may be made of any length desired and may or may not beprovided with cooling'means.

It will, of course, be understood that the inert gas or gases which are introduced with the explosive mixture may be derived from any source and may be of any character provided only that such gas or gases are substantially free from oxygen or hydrocarbon.

Having thus described my invention what I claim is:

1. The herein described method of operating two 15 admitting sai lower ingftwo cycle internal combustion eng'ineshaving acomgmression chamber,-,wh1ch con-1; ucing explosive mixture and spent gasestogether into the compression sists in intro chamber by drawing more or less of the throu a. cooler into spent gases from the exhaust oi the cylinder the compression cham- 1 her w1th rela y more 1958 mixture toi'rmake a full charge,

compressing said full char e in the compression chamber, charge into the cylinder at a ressure-,-compressing and igniting. e herein described method of operatcycle internal combustion engines having a compression chamber, which consists 1n intro ucing explosive mixture'and sfient "gases together into the com ression c amber, controlling the amount 0 explosive mixture admitted into thecompression chamber by controlling the admission of spent gases drawn from the exhaust to form Jointly a constant volume containing more or lessexplosive mixture, compressin the entire volume, admitting-it tothe cylinder lgmtmg.

3,. The herein described method of operafi= ing' two cycle internal combustion engines having sists in orming an explosive mixture, supplying s er ent gases from the exhaust through a coo its source drawing the explosive mixture and spent gases together into the compressionchamber, regulatin the admission of explosive mixture by t at a :lower pressure and compressingand a compression chamber, which cone regulation of admission of the, compressing the charge thus formed introducing said charge into the eninto the explosive mixture between. and the compression chamber,- 

